Pharmacokinetics of vitamin C: insights into the oral and intravenous administration of ascorbate

There is a strong advocacy movement for large doses of vitamin C. Some authors argue that the biological half-life for vitamin C at high plasma levels is about 30 minutes, but these reports are the subject of some controversy. NIH researchers established the current RDA based upon tests conducted 12 hours (24 half lives) after consumption. The dynamic flow model refutes the current low-dose recommendations for dietary intakes and links Pauling's mega-dose suggestions with other reported effects of massive doses of ascorbate for the treatment of disease. Although, a couple of controlled clinical studies conducted at The Mayo Clinic did not support a significant benefit for terminal cancer patients after 10 grams of once-a-day oral vitamin C, other clinical trials have demonstrated that ascorbate may indeed be effective against tumors when administered intravenously. Recent studies confirmed that plasma vitamin C concentrations vary substantially with the route of administration. Only by intravenous administration, the necessary ascorbate levels to kill cancer cells are reached in both plasma and urine. Because the efficacy of vitamin C treatment cannot be judged from clinical trials that use only oral dosing, the role of vitamin C in cancer treatment should be reevaluated. One limitation of current studies is that pharmacokinetic data at high intravenous doses of vitamin C are sparse, particularly in cancer patients. This fact needs prompt attention to understand the significance of intravenous vitamin C administration. This review describes the current state-of-the-art in oral and intravenous vitamin C pharmacokinetics. In addition, the governmental recommendations of dose and frequency of vitamin C intake will also be addressed.

A pilot clinical study of continuous intravenous ascorbate in terminal cancer patients

Case studies suggest that vitamin C, given intravenously at doses of 10-100 grams/day can improve patient well being and in some cases, reduce tumor size. While ascorbate is generally considered safe, clinical data on high intravenous doses is limited. Twenty-four late stage terminal cancer patients were given continuous infusions of 150 to 710 mg/kg/day for up to eight weeks. Blood chemistry and blood count profiles were obtained at roughly one-week intervals while patient health, adverse events and tumor progression were monitored. The majority of patients were vitamin C deficient prior to treatment. Intravenous infusions increased plasma ascorbate concentrations to a mean of 1.1 mM. The most common adverse events reported were nausea, edema, and dry mouth or skin; and these were generally minor. Two Grade 3 adverse events 'possibly related' to the agent were reported: one patient with a history of renal calculi developed a kidney stone after thirteen days of treatment and another patient experienced hypokalemia after six weeks of treatment. White blood cell counts were stable while hemoglobin and hematocrit levels dropped slightly during treatment, consistent with trends observed prior to therapy. Blood creatinine, BUN, glucose, and uric acid concentrations decreased or remained stable during therapy, suggesting that ascorbate infusions did not adversely affect renal function. One patient had stable disease and continued the treatment for forty-eight weeks. These data suggest that intravenous vitamin C therapy for cancer is relatively safe, provided the patient does not have a history of kidney stone formation.

Intravenous vitamin C as a chemotherapy agent: a report on clinical cases

A series of seven cases are presented in which intravenous vitamin C has been used as antineoplastic agent in the treatment of different types of cancers. The cancers cases reviewed are the following: Renal cell carcinoma (2), Colorectal cancer (1), Pancreatic cancer (1), Non-Hodgkin's lymphoma (2) and breast cancer (1). Toxic reactions were not observed at these high doses of intravenous Vitamin C. All patients were prescreened for Glucose 6--phosphate dehydrogenase deficiency before administering intravenous Vitamin C in order to prevent hemolysis

Erythrocyte membrane fatty acid composition in cancer patients

Essential fatty acids (EFA) have an important role in complex metabolic reactions. The metabolism of essential polyunsaturated fatty acids (PUFA) appears to be one of the critical targets in the complex metabolic stages that lead to, or are associated with cancer. The goal of our research was to analyze the erythrocyte specific types of membrane fatty acid content, level and distribution in cancer patients as compared to non-cancer patients. Changes in fatty acid composition may affect different aspects of cell structure and function, including proliferation. Analyses of RBCs membrane fatty acids were performed for 255 patients with different types of cancer (breast, prostate, liver, pancreas, colon, and lung), 2,800 non-cancer patients and 34 healthy volunteers. Our research study demonstrated a lower level of stearic acid and an increased content of oleic acid in RBC of cancer patients in comparison with control and non-cancer patients. According to the results of this investigation, the ratio of Eicosa pentaenoic acid (EPA) and Decosa hexaenoic acid (DHA) to Alpha-linolenic acid (ALA) may be useful to estimate PUFA imbalances in cancer patients. EPA and DHA acid may be recommended as supplementation and in addition to current therapy during cancer treatment